In the art of integrated circuits, there are various interconnection components used for interconnection purposes. For example, in 2.5-dimensional (2.5D) integrated circuits, interposers are used for bonding device dies thereon. Package substrates are also used to bond either device dies or interposers thereon. The interconnection components have metal bumps formed on the surfaces, and metal connections are built inside the connection components to interconnect the metal bumps. To improve the yield in packaging processes, defect connections need to be found
Some of the interconnection components, for example, interposers, may include thousands or more metal bumps, which are connected to other metal bumps on the same interposers through through-substrate vias (TSVs) and metal lines in the interposers. The sizes of the metal bumps became increasingly smaller, and may reach as small as 20 μm, for example. The probing of the metal bumps with such small size and such huge amount thus became more and more difficult. Accordingly, it is difficult to find defect metal connection through the probing of the metal bumps.